In the bottom of your electric mixer bowl put,
3 pks unflavored gelatin
1/2 cup cold water
In a med saucepan put
1 1/2 c sugar
1/2 c water
1 c light corn syrup
1/4 tsp salt
Bring to a boil and bring up to 240 degrees on a candy thermometer
With the mixer on low speed pour the hot sugar syrup mix over the gelatin slowly.Then raise the speed up to high and let run 12-15 min till very stiff, add vanilla around 10 min.
In a 9x13 cake pan dust liberal with powdered sugar, pour marshmallow on top of sugar spread evenly and powder the top. Let stand unwrapped at room temperature for up to 4 days to dry.
Cut in squares and roll cut edges in powdered sugar store in an air tight container.